Oxidation of organic materials with perchlorates: relevance to the chemistry on the Martian surface

Abstract

No organic materials have been found on the Martian surface, based on the results from the Viking and Phoenix missions. The Phoenix mission detected the inorganic perchlorates in the Martian soil. Perchlorates are potent oxidizing substances. The high-temperature oxidative properties of perchlorates may promote combustion of organics in pyrolytic experiments. This may compromise the ability of Phoenix's TEGA (Thermal and Evolved Gas Analyzer) experiments to detect organics. The high temperature conditions of TEGA instrument are not representative of the environment on Mars. In this paper we pose a question if organic materials can survive oxidation with perchlorates at less drastic temperatures. We have surveyed the literature on oxidations of various groups of organic materials by perchlorates. Several amino acids, notably glycine and alanine, are quite resistant to this oxidation. The same is true for some heterocycles, purines and purimidines. These organic materials may have survived perchlorate oxidation in the natural environment on Mars.